Sandstone (Quartzose)
Arenite (SiO2 principal composition)
Category
Browse tektite (natural glass) specimens identified by the Rock Identifier community.
Sandstone (Quartzose)
Arenite (SiO2 principal composition)
Artificial Rock Face (Faux Rock)
Glass Fiber Reinforced Concrete (GFRC)
Flint / Chert
Microcrystalline Quartz (SiO2)
Strawberry Quartz (Hematoid Quartz)
Silicon Dioxide with Hematite/Goethite inclusions (SiO2 + Fe2O3)
Yellow Quartz (Citrine Quartz / Milky Quartz)
Silicon Dioxide (SiO2)
Quartz Pebble with Mineral Inclusions
Silicon Dioxide (SiO2)
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Black Jasper with Quartz
Silicon Dioxide (SiO2) with impurities
White Quartz Pebble
Silicon Dioxide (SiO2) - Quartz
Quartzite
Quartzite (SiO2)
Chalcedony (Agate / Jasper Pebble)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Citrine Quartz
Crystalline Silicon Dioxide (SiO2) with Ferric Iron impurities
Unidentified gray stone
Likely quartz-rich stone; exact identification is not possible from the image
Quartz Pebble / Quartzite Pebble
SiO2 (Silicon Dioxide)
Quartz Pebble
Silicon Dioxide (SiO2)
Obsidian
Obsidian (volcanic glass), predominantly amorphous SiO₂
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz - SiO2)
Amethyst Cluster
Silicon Dioxide (SiO2) with iron impurities
Amethyst (or Rose Quartz)
Silicon Dioxide (SiO2)
Citrine
Silicon Dioxide (SiO2) with iron impurities
Pink agate (likely dyed or coated)
Microcrystalline quartz, SiO₂ (chalcedony/agate)
Smoky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
Vesicular volcanic rock, likely weathered pumice or scoria
Pumice/scoria; predominantly volcanic glass and feldspar, with possible iron oxides
Tumbled quartz pebble
Quartz (silicon dioxide, SiO₂)
Quartzite
Quartzite (primarily SiO2)
Sandstone
Arenite
Sandstone
Arenite (primarily SiO2 with trace Fe2O3)
Iron-stained sandstone or weathered ironstone concretion
Quartz-rich sandstone, locally cemented by iron oxides (hematite/goethite); exact identification requires testing
Amethyst
Silicon dioxide with iron impurities (SiO2:Fe3+)
Citrine (Quartz variant)
SiO2 (Silicon Dioxide)
Black Onyx (Tumbled)
Chalcedony (Silicon Dioxide, SiO2)
Sandstone
Arenite (SiO2 primarily)
Sandstone with Iron Staining
Arenite with Limonite/Hematite inclusions (SiO2 + Fe2O3/FeO(OH))
Rough Sapphire
Corundum (Al2O3)
Amethyst
Amethyst (Silicon Dioxide with iron impurities), SiO2
Quartz Pebble in Arkosic Sand
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Quartz (Variety: Agate / Chalcedony)
Silicon Dioxide (SiO2)